The Japan of the early 20th century is a very interesting place and there's A LOT of factors that went into how they acted during the war both towards the other peoples of Asia as well as towards the western Allies. But in the end the thing I have learned is that they are surprisingly normal people like you and me who due to cultural manipulation, some really through propaganda, and (like the rest of the world at the time) racism. Were used by a select few higher ups who were making a wild grab for power with no regard for the lives of the Japanese or those they fought.
It's a little long but here's what a veteran said on his time in the war in China and I find what he says a window into what they did to normal people. (In the war an estimated 20,000,000 Chinese died with 80% of that being civilians, it's almost a mirror of the German rampage through Russia).
"I was ordered to lead a platoon. My company commander took me to meet my men. That's where I first set eyes on the soldiers I was to lead. What shocked me, was the look in their eyes. Hardly human. The eyes of tigers, of panthers. They had murderous, triangular eyes. They were brave warriors who'd been in the thick of battle again and again. I had no expierence at all. Knew nothing of war. Could I really manage these guys? They shook my confidence in my ability as a leader.
Starting the next day, the officers-in-training assigned to that regiment, there were 22 of us in all. From the next day, we all began a week-long training session for field platoon leaders. Our education began. The last day, at the end of that week, they tested our courage, of the new officers. We had to slice the head off a living person. 2nd Lieutenant Tanaka began by saying, 'This is how you cut off a human head.' Then he showed us by example.
There were 20 or so Chinese prisoners, blindfolded off to one side. Apparently, they'd been taken in an operation right before I arrived. [2nd Lt. Tanaka] Stood behind, held the sword high, at an angle. All at once with a yell...the head flew two meters. Fountains of blood spurted from the carotid arteries, and then it rolled and plopped in a hole. It goes without saying, that this was a first for us. How do you say, the awfulness of it. I saw it and was paralyzed. My body went rigid.
Then we had to do it, starting on the far right. I was 4th in line and it was my turn. In that moment, I thought. 'Can this be allowed?" After all, I'd read my Kant, his critique of pure reason, and the idea of personal responsibility, I considered myself something of a Humanist. And the thought 'Can this really be allowed to happen?' crossed my mind. But if I screwed up then, I knew I'd be done for. 'All I had to do, was exactly what he'd just shown us', I told myself as I walked. And that's exactly what I did, and I sliced the neck easily.
In that instant, something thudded in my belly. Something like confidence, I'm not exactly sure what. But some of the others, there were 22 of us in all, lost their grip and only wounded the Chinese, who reeled like madmen. The officer screamed 'stab him from behind,' but they missed. 'Outta the way!' Then 2nd Lt. Tanaka came over, kicked him, and sliced off the head. So that's how it went on. By the time all 22 were finished, it was a sea of blood. And finally, there was only one prisoner left. Tanaka looked at the officers and said, 'anyone want to volunteer?' A veteran 1st Lt. raised his hand. He walked forward carrying a package. Apparently hed recently purchased a real sword. And he wanted to try it out. His movements were the absolute picture of calm. Just like a walk in the park. He undid his package, pulled out his sword, sliced, and done.watching him move, I thought I'd have gone out of my mind in his situation. But he'd pulled it off in the most matter-of-fact way. I was really shocked.
That night at roll call, I faced my men. I didn't feel the slightest inferiority. Nor did I see an evil look in their eyes. No doubt the moment Id sliced off a head for myself, my own eyes had changed.' -Tominaga Shozo Former 1st Lieutenant, IJA